I've been trying to change my own TB since last week. I've got the tear down and put back together to where I can do it with my eyes closed. I think I've spent a total of 15 hours or so on this "simple" project. First it clattered under load like getting bad gas. Then it ran nice & quiet but had no power and would stall most of the time. Then it ran better, but when I went to pass, the belt must have jumped enough to have it die and not restart. After I had it towed home yesterday morning, I spent 5 hrs and 3 teardowns to get it where it ran smoothly and was like it was before the belt change. This morning I could feel it loosing power again and try to stall. I'm off tomorrow, so I'm headed to the junk yard where I know there is a low mileage '91 and get the TB tensioner unit and while I'm at it go through the motions like it were mine to find TDC and see where all the timing marks are. I know that's where my problem lies (hopefully). Any other advice?
Like I said, one more time........

:-(

'86 240DL 335K with auto trans.